EXOX Bike Computer Bike Rack Cycling Odometer Speedometer Wireless Waterproof Bike Odometer with Multi Function LCD Backlight Suitable To All Types Of Bicycles:road cycling,mountain biking,folding bike,common bicycle.Perfect device can also be used for hiking,climbing and many other fun,adventurous outdoor activities. Multi-function:functions as a bicycle speedometer and odometer,measuring speed,distance and riding time.Displays speed/max speed/average speed/trip distance/total distance/elapsed time/clock/Freeze Frame Memory/Auto sleep.You can arrange cycling life scientifically. Auto Sleep/Wake:auto standby within 300 seconds during inactive use,CLK Data will stay,it will start up if any button is press and detect any movement. Wireless And Waterproof Design:makes it more convenient and durable.Don't worry about a bunch of tangled wires on your handlebars anymore.No need to worry about rain. Backlight Function: Backlight will turn on when press any button during 18:00pm and 8:00am.The backlight can be set in either green and white color.Built-in steel ball switch that will shake when receiving signals,computer will be automatic awake from sleeping mode.In the mean time you may hear slight rattle from the device.It's common phenomenon as steel ball is working.No worry about it.